Day of the Dead(1985) [Private Johnson]: Accidentally shot to death by Phillip G. Kellams, when Phillip's throat is torn out by a zombie, causing him to fire wildly. (Thanks to Wen)

From Dusk Till Dawn(1996) [Sex Machine's Buddy]: Killed by the vampires during the big massacre in the bar.

Land of the Dead(2005) [Bridgekeeper Zombie]: Plays a zombie, having died some time before he first appears.

The Hills Have Eyes(2006) [Cyst]: Hit in the face with an axe by Aaron Stanford in the desert.

Diary of the Dead(2007) [Zombie Surgeon]: Dies of the zombie virus, shortly before his first appearance; he appears as a zombie in the hospital, and dies once again when Scott Wentworth shoots him in the head.